Costello k holford



(No Model.) G. N. HOLFORD.

GAISSON FOR SHIPS.

No. 538,780. Patented May '7, 1895.

INVENTOI? A TTORNEYS,

. UNITED STATES PATENT OFFICE.

COSTELLO N. HOLFORD, OF WASHINGTON, DISTRICT OF COLUMBIA;

'CAISSON FOR SHIPS.

SPECIFICATION forming part of Letters Patent No. 538,780, dated May 7,1895.

. Application filed July 7, 1894:. Serial No.516,873. (N model.) i

so that the whole of the hull may, in separate sections, be madeaccessible from the keel to the water line, for the purpose of cleaning,re-

painting or repairing, Without the ship going into a dock,

tolerably still.

It also has for its object to provide a detachable caisson of few parts,which can be easily connected with the hull at the points desired andwhich will effectively serve for its intended purpose.

With other objects in view, which hereinafter will appear, the inventionconsists in such novel features of construction and peculiar combinationof parts, as will hereinafter be first described in detail, and then bespecifically pointed out in the appended claims, reference being bad tothe accompanying drawings, in which- Figure 1 is a diagrammatic planview ofthe hull of a vessel, illustrating the manner in which thesecuring-ribs and the caisson-plates are arranged to project from thesides thereof. Fig. 2 is a diagrammatic side view thereof. Fig. 3 is atransverse sec ion thereof. Fig. at is a horizontal section'of a portionof the hull, showing a caisson-section attached. Fig. 5 is a verticalsection of the same. Fig. 6 is a detail perspective view of one of theribs. Fig. 7 is a detail view of one of the stern-ribs formed with anopening to receive the propeller-shaft,

and Figs. 8 and 9 illustrate the flap-valve or gate for making suchopening water-tight.

Referring to the accompanying drawings, A indicates the hull of avessel, on which at the points of attachment for the caisson, a seriesof rows of screw bolts B is inserted each row consisting of six oreight, each arranged perpendicular from the water line to the keel.These bolts are secured permanently to the hull in any approved manner,preferably by screwing the ends therein as shown in Fig. 4,

and which can be used in any port or even in mid ocean when the wateris,

and such bolts when not in use have their threads filled with far orsome similar substance to prevent corrosion. To these bolts is connecteda system of ribs 0, the number depending on the width of the caisson andthe length of the hull. If the caisson is to be ten feet wide, theremust be one rib at each end of the hull and one at every interval of tenfeet of such hull. The ribs 0 are formed preferably of half inch steeland are of a length sufficient to extend from the keel to about a footabove the water line.

In practice a series of ribs 0 is provided, each rib being adapted tofit on a particular line on the hull, and for such purpose such ribshave their abutting faces curved and shaped to exactly fit such sectionportion of the hull to which they are to be connected, and such abuttingedge is lined with rubber c to make a water tight joint, it beingobvious that other means may be employed for rendering the joint watertight without departing from my invention. The outer edges of all theribs on which the capsD (presently referred to) are to be placed ashereinafter described are of the same length and curv-' ature. At thelower end of every section a cross rib C is run along the keel from oneperpendicular rib to the other, and such rib C is of the same width asthe ribs 0, so as to bring its outer edge flush with such side ribs, toform a base for securing the lower end of the cap D. The cap D' theconstruction of which is best understood by reference to Figs. 4 and 5,may be of convenient width, say ten feet, and is of a length the same asthe ribs C, and of a depth sufficient to form a compartment. with roomenough for men to work inside. Such cap is made of thin steel or ironplate, corrugated to give the greatest resistance to pressure with theleast weight, and only thick enough to resist safely, the waterpressure. The caps D have apertured earsd which are adapted to fit onsimilar ears 0 c on the ribs O and 0 when fitted in position rubberpacking strips E being interposed to render the joints water tight. Whenthe cap is placed in position the same is braced by detachable crossrods F as shown in Figs. 4 and 5.

In cases where the vessel has twin screw propellers, the ribs for thatportion of the hull where the propeller shaft stands out are madeseveral feet (more or less) wide, and formed with a slot or cut outportion 0 as shown in Fig. 7 which forms a passage for such shaft. Whenthis rib is placed in position the slot is made water tight, by means ofa double flap lid G hinged to the rib, which when the water is pumpedout of the caisson is automatically closed by the water pressure fromthe outside which forces it closely over the slot.

Owing to the change of curvature of thehull at least three of the capsDare provided, one for the region near the bows,one for that about thestern, and one for the amidships, to fit the varying shape of the hull,in these parts, without unnecessary width of ribs. In each of theseregions the outer edges of all the ribs must lie in the same plane sothat the cap in each section will fit all the ribs of its respectivesection.

While I prefer to use but three caps it is manifest the greater thenumber of caps used the greater the surface of the hull that can be madeaccessible at once.

The manner in which my improvements are used is as follows: \Vhen it isdesired to apply the caisson, the ribs 0, C, which are to form part ofthe sides and bottom of the caisson are first attached to the bolts atthat part of the hull desired. The cap is then let down and its edgesplaced on the outer edges of the ribs and fastened thereto, which may bedone by men with divers helmets or otherwise. YVhen the caisson cap isin place, the water is pumped out of such caisson section, therebyleaving the outer surface of the hull for the width of the caisson asaccessible as if the vessel were in dry dock.

It should be stated that at each division line between the severalsections or regions of the hulltwo ribs are to be arranged, one for eachof the two caps which will come upon this line.

Having thus described my invention, what I claim, and desire to secureby Letters Patent, is-

1. As an improvement in caissons, the combination with a vessel havingits hull provided with a series of rows of projecting studs arranged atpredetermined distances apart, of a detachable housing having closedsides and bottom portions, and members curved to fit the hull and toengage and be secured to any pair of rows of the hull studs, as shownand described.

2. The combination with the hull A having a series of bolts arranged inperpendicular rows from the keel to the water line, of detachable ribssecured to such bolts having a contour to snugly fit the vertical sidesof the hull, a horizontal rib for joining the vertical ribs at the keelend, a cap plate or housing, and means for detachably connecting suchribs and housing substantially as shown and described.

3. The combination with the hull having a series of vertically arrangedbolts, and the propeller shaft section disposed on the outside of thehull, of ribs adapted to be secured to such bolts having slots orcutaway portions whereby they are adapted to fit over the shaft, cut 05devices held to operate over the said slot, and arranged to be heldclosed by the outside water pressure and a cap plate or housing adaptedto be detachably connected to the ribs all arranged substantially asshown and described.

4.. The combination with the hull A having a series of screw boltsprojected on its outside, arranged in vertical rows, ribs detachablyconnected to such bolts, a transverse rib connecting the vertical ribsat the keel end, a cap plate or housing detachably secured to the outerface of the vertical and horizontal ribs, and the brace rods allarranged substantially as shown and described.

COSTELLO N. IIOLFORD.

Witnesses:

FRED G. DIETERICH, SOLON C. KEMON.

